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By P. W. Jeran, M. C. Irani, D. H. Lawhead

The Beckley mine is one of five new mines in a heretofore unmined portion of the Beckley coalbed. The remoteness of these new mines from prior mining and their greater overburden preclude applying methane emission experience obtained in the old mines. Four sections of the Beckley mine were monitored. The data gathered show that variations in methane emission cannot be explained by variations in coal production. Although overburdens varied by as much as 30 pct, no correlation with methane emissions could be determined. The rib emissions increase with increased length of rib from a section advancing into virgin coal and do not decline over a prolonged idle period (32 days) whereas some decline has been measured for a section not mining into virgin coal. The indication is that degasification prior to mining will reduce the hazard of methane emissions in this area of the Beckley coalbed.

Jan 1, 1977

By Richard G. Geyer

One aspect of a program to improve the chances of survival following coal mine disasters is the development of a communications system which will allow surviving miners to make their circumstances known to rescue teams. Various communications techniques can be considered, including electromagnetic systems, acoustic systems, and hybrid systems. The electromagnetic and acoustic systems would be independent of existing mine communications systems and set up specifically for use in emergencies. Hybrid systems might use a short emergency link to existing telephone systems in the mine. Many variations are technically possible, and the primary task is in evaluating the relative merits of each, so that the most workable system can be selected.

Jan 1, 1973

By Jr. Harty

Intensive work on the deoxidation of steel with manganese-silicon alloys by the U. S. Bureau of Mines has shown that the use of those alloys, which may be produced from our domestic manganese ores, would decrease the ferromanganese requirements of a very large tonnage of our steel by from 60 to 80 per cent and in some cases by 100 per cent. The open-hearth heats made with these alloys have been of excellent quality. The tonnage of our ferro-grade ores Which has been made available by the bureau's ore-dressing studies, combined with the products resulting from such processes as those developed by the bureau and by Bradley for Cuyuna ores, should easily fill our reduced ferromanganese requirements when manganese-silicon alloys and ordinary Spiegel are used in the way described in this report. There are no technical difficulties in the application of this practice, and any difficulties involved in its wide and immediate application would only be those arising from habituated ideas of the necessity of ferromanganese. General acceptance of this practice and development of the available sources of domestic ferro-grade material by already proven processes should make this country independent of foreign ores. This paper resents the results of work done under a cooperative agreement between the Pittsburgh Experiment Station of the United States Bureau of Mines and the Carnegie Institute of Technology, the Metallurgical Advisory Board, and the University of Pittsburgh, Pittsburgh, Pa.; between the Mississippi Valley Experiment Station of the United States Bureau of Mines and the Missouri School of Mines and Metallurgy, Rolla, Mo.; between the North Central Experiment Station of the United States Bureau of Mines and the University of Minnesota, Minneapolis, Minn.; and between the Rare and Precious Metals Experiment Station of the United States Bureau of Mines and the University of Nevada, Reno, Nev.

Jan 1, 1931

By C. H. Herty

Intensive work on the deoxidation of steel with manganese-silicon alloys by the U. S. Bureau of Mines has shown that the use of those alloys, which may be produced from our domestic manganese ores, would decrease the ferromanganese requirements of a very large tone of our steel by from 60 to 30 per cent and in some cases by 100 per cent. The open-hearth heats made with these alloys have been of excellent quality. The tonnage of our ferro-grade ores which has been made available by the bureau's ore-dressing studies, combined with the ,products resulting from such processes as those developed by the bureau and by Bradley for Cuyuna ores, should easily fill our reduced ferromanganese requirements Then manganese-silicon alloys and ordinary spiegel are used in the way described in this report. There are no technical difficulties in the application of this practice, and any difficulties involved in its wide and immediate application would only be those arising from habituated ideas of the necessity of ferromangenese. General acceptance of this practice and development of the available sources of domestic ferro-grade material by already proven processes should make this country independent of foreign ores.

Jan 1, 1931

To provide a method for locating trapped miners promptly and accurately. The Approach: Develop a wireless emergency system that is intrinsically safe, compact, easy to operate, reliable, sturdy, and economical. How It Works: A (one transmitter has been developed under Bureau of Mines contracts. The transmitter weighs only a few ounces, is powered by a cap lamp battery, arid can be carried on the miner's belt. A compact loop antenna, which could either be carried by the miner or strategically located in the mine, is used to generate a magnetic field that is sensed by a mobile receiver on the surface. When needed, the antenna is deployed to form a single loop. In mines where the overburden is less than 600 feet, a loop of No. 19 wire approximately 30 feet in circumference is normally adequate. This antenna weighs less than one half pound. In deeper mines, a heavier wire and bigger loop is required; a No. 10 wire deployed around a pillar has been used.

Jan 1, 1974

Assure fail-safe stopping of a mining vehicle immediately following a loss of electric power. Approach A separate emergency brake system which actuates when electrical power is interrupted, was installed on several mining vehicles and tested in a long-term underground mining demonstration. How It Works Separate, spring-actuated brakes, which press against brake discs, are used to stop the vehicle following power failure. To allow norm al movement of the vehicle, hydraulic oil under pres? sure from the vehicle's hydraulic system is directed to a spring? loaded piston in each emergency brake housing. That pressure causes the piston to compress the spring and relieves the spring pressure against the puck, thereby allowing the brake disc to turn freely. See Figure 1 A. If the electrical power fails or if the machine is turned off, a valve in the hydraulic line to the emergency brakes opens. That valve, shown as ?Solenoid Valve (automatic)" in Figure 1, which is normally held closed by its electrical solenoid while the vehicle is electrically powered, is opened by the spring in the valve assembly. The pressure in the hydraulic line which is connected to the emergency brakes then drops to

Jan 1, 1978

In the last few decades, a considerable amount of effort was directed at accurately determining the coal pillar strength to use for safely designing coal mines. The outcome of this early work was the well known Obert-Duvall, Holland-Gaddy, Bieniawski, and Salamon-Munro equations for coal pillar strength. All of these equations were developed for, and were calibrated with, pillars in a large room-and-pillar area such that the loading could be determined using the "tributary-area" theory. In order to account for the abutment loads associated with full-extraction mining, the empirical methods have typically adopted a simple conceptualization of the abutment load through use of an "abutment angle." Short of a complete numerical or analytical analysis of the coal seam and surrounding strata, very little work has been Fretted toward refining the empirical analysis of pillar loading. It appears that the vast majority of the research has been directed at determining the pillar strength, the numerator of the safety factor equation, when the denominator of the safety factor equation, the pillar loading, plays an equally important role in pillar design. This paper will address the deficit of pillar loading research by exploring the accuracy of the empirical abutment load calculations using insight provided by an elastic overburden model, a laminated overburden model and field observations. Ultimately, it is determined that a constant abutment angle probably over-predicts the abutment load as the mining depth increases.

By John Durkin, Harry Dobroski

This paper presents a general overview of the Bureau of Mines' programs in the areas of operational and post-disaster communications. These programs encompass both hardware developments and system evaluations. Topics discussed include a new visual paging system compatible with existing pager phone lines, a means of modifying commercially avail able pager phones to permit selective paging and message leaving, a multiplexed telephone system that uses twisted shielded pair and requires no central control, medium frequency hardware developments, and a manual for mine communications. Research has continued in the area of post-disaster location and communications. This research is based on seismic and electro- magnetic techniques. Each has been extensively studied and field tested to better understand its ability to perform effectively. A brief description is given of the post-disaster program. Results are promising and provide insight into future areas of research.

To determine the effectiveness of multiple types of fire sensors for early and reliable mine fire detection. Background The National Institute for Occupational Safety and Health (NIOSH) has evaluated the effectiveness of multiple types of fire sensors for early mine fire detection and nuisance signal discrimination. Reliable early fire detection in underground mine can be hindered by false fire alarms produced by carbon monoxide (CO) and smoke particulate emissions from diesel equipment, welding, and metal-burning activities. Another false fire alarm source is the cross-interference of hydrogen (H2) produced by battery-charging operations with a CO sensor's chemical cell. Workers can learn to ignore repetitious "false" alarms associated with these emissions. This jeopardizes their safety in the event of a mine fire.

Sep 1, 2002

By Ivette E. Torres

Bulk carriers, freighters, and tankers are the three classes of seagoing vessels engaged in transporting mineral commodities. However, vessels in these classes are not exclusively devoted to mineral commodity transport. Bulk carriers move considerable tonnages of agricultural products as well as crude minerals, their concentrates, mineral fertilizers, and the like. Freighters, owing to their great variety, can be devoted wholly to hauling mineral products or wholly to nonmineral goods, as well as carrying mixed mineral commodities and nonmineral commodities. They include general cargo ships, full container ships, partial container ships, roll-on/roll-offships, and barge carriers. Tankers, although largely engaged in moving crude oil and refinery products, also transport liquid chemicals, molasses, wine, liquefied natural gas, and other fluids. Although physical characteristics of vessels such as size, draft, crew requirements, type of propulsion system, ratio of gross tonnage to cargo tonnage, and fuel costs have undeniable influences on shipping industry performance, problems of and changes in the quantity and types of materials moved also significantly affect the shipping sector of the world economy, and thus have a bearing on the minerals sector of that aggregate. Unfortunately, comprehensive global data reflecting changes in these critical variables are not published.

Jan 1, 1994

By J. M. Stuve

Heat of solution measurements of high-purity neodymium metal and neodymium trichloride (NdCls) in 4.360 molal hydrochloric acid (HCI) were used to determine the standard heat of formation (6EPr) of NdCls? From solution data obtained, the heat of formation of NdCls (c) was computed as -248,970 ±260 cal/mole at 298.150 K.

Jan 1, 1965

Prevent collisions between large mine-haulage trucks and smaller vehicles parked in areas not visible to the haulage-truck operator, Approach Two electronic systems were developed to detect the presence of vehicles in the blind areas of a parked haulage truck. The systems can warn haulage truck operators of presence of vehicles that are blocked from view. The systems do not apply for trucks in travel. How It Works The systems use electronic transmitting techniques-one system is based on low-frequency radio waves and the other on very-high-frequency radio waves. Each system requires that a signal transmitter be mounted on the smaller vehicle to be detected. Continuous signals from this transmitter are sensed by receiving antennas mounted on the right front and rear of the large haulage truck. Upon receiving a signal, the receiver energizes warning lights and a buzzer in the cab of the haulage truck, alerting the operator to a possible collision hazard. Detection distance is adjustable, depending upon the size of the haulage truck, but a minimum of 30 feet was the design goal.

Jan 1, 1990

By Andrew B. Cecala, Edward D. Thimons, George W. Klinowski

The U.S. Bureau of Mines has designed and evaluated total mill ventilation systems at two different mineral processing operations. Both systems have proven very effective at reducing respirable dust levels throughout the mill in a cost-effective manner. A 25,500-cfm system installed at a clay processing mill provided approximately 10 air changes per hour. This system reduced respirable dust concentrations by approximately 40 pct throughout the mill building. The second evaluation was performed at a silica sand operation. Tests were performed with 50,000 and 100,000 cfm of ventilation to the mill building, corresponding to 17 and 34 air changes per hour. Average mill-wide respirable dust reductions were 36and 64 pct, respectively. Not only did these systems reduce respirable dust concentrations and increase visibility throughout the mills, they were also easy to install and required minimal maintenance. A total mill ventilation system provides a general purging of the mill air; the system should be viewed as a supplemental technique to assist other dust control systems in operation.

Jan 1, 1993

By Lon D. Santis

This paper presents data and theorem to calculate the risk of experiencing undesirable lightning related events while blasting or while engaged in other lightning sensitive activities. The paper provides an overview of lightning hazards in blasting operations and a brief history of lightning related blasting accidents. Lightning continues to be the primary cause of premature initiations of explosives in mining, on average, over two such incidents are reported to the Mine Safety and Health Administration (MSHA) each year. The energy contained in lightning discharges and how this energy sets off explosives in mining is presented. Three categories of lightning warning methods: public media, lightning detectors, and atmospheric electrostatic field measurement are discussed. The remainder of the paper presents recently acquired data on the spatial characteristics of lightning development. This data is used to estimate the risk assumed by blasters under certain conditions. Risk estimations are made for electric and nonelectric blasting if persons are evacuated when cloud-to-ground (c-g) lightning approaches within a certain distance. For example, about 0.6% of all c-g lightning strikes have no other c-g lightning strikes within 25 miles in the previous 30 minutes. The paper shows that a typical blaster using nonelectric initiation in a high lightning density area with a 100% accurate lightning detector set to alarm at 25 miles would have a lightning caused unplanned detonation every 14,000 years

By John R. Benham

The Long Swamp RARE II area contains no prospects, claims, or mines. It has a low potential for ore deposits. There are no geothermal, oil, or gas leases in the area. APPRAISAL There are no mining districts in the study area. The nearest is Chewack Mining District, which is 6 mi (9.6 km) north of the area. This district had numerous claims located for tungsten; the principal tungsten ore mineral was wolframite. Wolframite was found here in 1898 by surveyors of the International Boundary Commission. The area was staked in 1908 and developed during 1915 and 1916. Only in 1936 was ore shipped; the 30 ton (27.2 t) shipment proved to be unprofitable for the claimants (Culver, 1945, p. 41).

Jan 1, 1982

By S. J. Page, J. A. Organiscak

Airborne respirable dust surveys were conducted at six surface coal mines to investigate the effectiveness of dust control methods used on rotary rock drills and bulldozers. Dust controls commonly used on drills include a dry dust collection system, exhausting from a shrouded area around the collared hole, and an enclosed drill operator cab, filtering airborne dust from the cab. Bulldozers are also typically equipped with an enclosed operator cab as a dust control measure. Airborne respirable dust sampling was conducted near each equipment's source of generation and inside its enclosed cab. Silica analysis was performed on the dust samples to determine the percent silica content in the dust generated at the six mining operations. An additional eight- month follow-up of dust sampling was also conducted in the enclosed operator cabs of several rock drills and bulldozers. Data were analyzed for long-term variability of accepted control methods to abate dust and silica levels. The highwall rock drill was the major and most variable dust source as compared to the bulldozer, generating dust levels, on average, one order of magnitude higher than dust levels of the bulldozer. Four of the six drills surveyed had dust containment and capture problems at the shrouded drill table above the lple. Repairs or modifications to three of the drill dust collection systems were shown to reduce dust levels by more that 50% next to the shrouded drill table. The enclosed operator cabs provided more than 90% and more than 40% lower dust levels than at the dust source for the drill and bulldozer, respectively. Long-term sampling of several of these highwall drills and bulldozers showed that the dust levels in the drill cabs were frequently higher than 0.2 mg/m3 and more variable than in the bulldozers. The bulldozer dust levels were frequently below 0.2 mg/m). Future research should focus on improving some of the deficiencies present in the drill's primary dust collection system, and developing quality control methods to ensure the integrity of enclosed cab protection for equipment operators.

Develop technology for preparing thick corrosion-resistant coatings and electroforms of iron-chromium-nickel alloys. Approach To reduce the United States' dependence upon foreign sources for supplies of strategic and critical metals such as chromium, cobalt, and nickel, new technology must be devised to conserve these valuable commodities. One approach being investigated by the Bureau of Mines is the use of a modified-aqueous-electrodeposition method to prepare thick (-25 µm), complex alloy coatings (e.g., stainless steel composition) with properties similar to the commercial alloys. An alloy coating on a low-alloy steel or carbon steel substrate would require significantly less strategic and critical metals than those contained in an equivalent mass of the commercial alloy. Coatings applied to appropriate mandrel materials make possible the preparation of intricately-shaped alloy electroforms (near-net-shape parts). As a result, the loss of valuable metals associated with machining finished products would be minimized.

Jan 1, 1986

Enhance coal mine worker safety and productivity by developing a means to control and predict coal mine mountain bumps. Approach The Bureau of Mines has been engaged in extensive research to understand coal mine mountain bumps and their effect on underground coal mining in the United States. Information was collected on the geologic conditions, mining techniques, and engineering parameters at five mountain-bump-prone mines. Although research has not yet evolved to the point where mountain bumps can be effectively predicted or controlled, such studies are invaluable for providing clues that can lead to the development of mountain bump mitigation technology. Case Study Results and Recommendations Mountain bumps in coal mines are explosions of the coalbed that violently release the strain energy stored within it into openings created by mining. Such an event is not only dangerous to mine workers, but can cause substantial amounts of damage to mine equipment, resulting in productivity loss and downtime. In a coal mine, the occurrence may cause coal to be expelled violently from the coal face or coal pillars or cause the mine floor to heave suddenly. Coal bumps are usually accompanied by a very loud noise and tremors or vibrations. Such ground failure:; usually occur in the vicinity of an active gob line in an active retreating room-and-pillar panel, or at or near the face in an advancing or retreating longwall mining panel.

Jan 1, 1989

By Charles L. Kimbell

Updated information on market economy country petroleum industry capital and exploration expenditures by geographic area (table 14) was not available in time for inclusion here, thus this information remains the same as was presented in the previous edition of this chapter. The salient statistics on U.S. foreign investment in mineral industry activities (table 15) as reported by the U.S. Department of Commerce has been revised to show the latest information for the years 1986-90.

Jan 1, 1993

By Kevin Connor

The mineral industry in Burundi was a minor contributor to the country's gross domestic product (GDP), which was estimated at just $1 billion for 19812. Coffee and tea continued as the Nation's major export commodities. Mineral exports consisted of small tonnages of wolframite, cassiterite, and baetnasite. Burundi's trade balance of payments situation worsened in 1981, with import payments more than double export revenues. Petroleum imports alone equaled 46% of the export revenue total. By year-end, the only indigenous fossil fuel source to have been found in Burundi was peat, which the Government had been attempting to develop to alleviate some of the petroleum import requirements. In June 1981 the Irish Peat Development Authority, Bord na Mona, signed a 4-year contract with the Burundian Government to supply technical staff for the ongoing peat project work there. Funding for the project was provided by the VS. Agency for International Development and the Government of Ireland. The new contract, which was an extension of ongoing peat research there, represented Burundi's increased awareness of the value of its large peat reserves for both energy and agricultural uses. At yearend, Burundi's Ministry of Public Works and Mines was does to selecting a contractor to study the feasibility of developing Burundi's phosphate deposits. The study would determine the potential for establishing fertilizer production facilities based on the country's phosphate reserves at Matongo-Bandaga, The study's specific objectives are to prove mineral reserve tonnage and grade, draw up mining and processing facility designs, estimate capital and production costs, and conduct a regional market and distribution survey. The cost of the study was estimated at slightly over $1 million, and it should take approximately 16 months to complete. The proposed project will mark the Burundian Government's first step in its plan to exploit on a large scale its natural mineral resources for advancing its agriculture-based economy. Burundi was dependent on imports, which are expensive to transport inland from coastal ports, to supply its domestic requirements for fertilizer. It was planned that part of the fertilizer production from the

Jan 1, 1983